FILL ONCE WHITE 325ML. Fill Once is a revolutionary new ready mixed filler made with Expanded Micro-Sphere Technology (EMT) making it ideal for filling large or small holes in ONE application without the need for building up of layers. Formulated to outperform conventional fillers, Fill Once provides a smooth, fine finish that won’t shrink back after setting and will only require minimal or no sanding. Fill Once will set hard so it can support nails or screws directly into solid substrates. Fill Once is ideal for repairs to plaster, wood, brick, stone and rendering.